Method of making a disposable filtering device

ABSTRACT

A disposable conical filtering device having gauze covered openings is characterized by structure providing a more rigid and efficient filtering device which is more convenient in use and which is particularly adapted for straining paint or the like. The novel method of producing the present filtering device is characterized by novel steps including die-cutting blanks from a strip of material and assembling the same in a rapid and economical manner with a minimum of waste material.

J. P. WHELAN June 12, 1973 METHOD OF MAKING A DISPOSABLE FILTERINGDEVICE Original Filed Oct. 11, 1967 5 Sheets-Shet 1 W R Wezazz,

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METHOD OF MAKING A DISPOSABLE FILTERING DEVICE Original Filed Oct. 11,1967 5 Sheets-Sheet 5 United States Patent 3,738,889 METHOD OF MAKDIG ADISPOSABLE FILTERING DEVICE James P. Whelan, North Marshfield, Mass,assignor to Ad-Tec Products, Inc., North Quincy, Mass. Originalapplication Oct. 11, 1967, Ser. No. 674,624, now Patent No. 3,567,033.Divided and this application Mar. 1, 1971, Ser. No. 119,688

Int. Cl. B3211 31/00; BOld 39/08 U.S. Cl. 156-263 7 Claims ABSTRACT OFTHE DISCLOSURE This application is a division of my copendingapplication, Ser. No. 674,624, filed Oct. 11, 1967, now U.S. Pat. No.3,567,033.

The invention has for an object to provide a novel and improveddisposable filtering device characterized by rigid structure which isconvenient in use and which is particularly adapted for straining paintor other liquids.

The invention has for another object to provide a novel and improvedmethod of manufacturing a disposable conical filtering device of thecharacter specified by which the device may be produced in a rapid andeconomical manner with a minimum of Waste material.

With these general objects in view and such others as may hereinafterappear, the invention consists in the filtering device and in the methodof making the same as hereinafter described and particularly defined inthe claims at the end of this specification.

In the drawings illustrating the preferred embodiment of the invention:

FIG. 1 is a developed view of a blank from which the present filteringdevice is formed;

FIG. 2 is a plan view of the filtering device in assembled form;

FIG. 3 is a side elevation of the filtering device shown in FIG. 2;

FIG. 4 is a plan view diagrammatically illustrating the initial steps inthe method of die-cutting and separating successive blanks in theproduction of the present filtering devices;

FIG. 5 is a perspective view more or less diagrammatically illustratingthe various steps in the method of producing the present filteringdevices;

FIG. 6 is a side elevation diagrammatically illustrating apparatus forcompleting the production of the present filtering devices in accordancewith the present method;

FIG. 7 is a cross sectional plan view of a cone forming mandrel as seenfrom the line 7-7 of FIG. 6;

FIG. 8 is a plan view detail of a forming mandrel as seen from the line8-8 of FIG. 6 and showing a blank about to be wrapped thereabout; and

FIG. 9 is a view similar to FIG. 8 and illustrating the blank wrappedabout the forming mandrel.

In general, the present invention contemplates a filtering device orstrainer of novel and improved construction and particularly a conicalstrainer of the disposable type having gauze covered openings therein.The invention further contemplates a novel and improved method of makinga filtering device which results in a saving of paper and cloth andwhich produces a more efficient and convenient filtering device.

In practice, most paints and enamels as they are manufactured andpackaged in the factory are not always entirely free of foreignparticles inadvertently included therein and which might causedifficulty when used in spray painting machines. For this reason, allpaints deposited in such machines are first strained or filtered. Priorto the present invention, disposable conical or funnel shaped paintstrainers have been available which are made of a fibrous material, suchas paper, and which are provided with gauze covered openings throughwhich the paint is strained. In the production of the conical strainers,the blanks are die-cut from a strip of heavy paper or other fibrousmaterial; the openings are provided with a gauze covering; and theblanks are then formed into conical shape and provided with overlappingadhesively secured side seams to complete the production.

In the manufacture of prior conical paint strainers, the pattern of thedied-out blank from which the cone is formed was such as to requiresuccessive patterns cut from a web of material to be spaced apartlongitudinally and also spaced from the edges of the strip, such spacingrepresenting waste material which adds considerably to the cost ofmanufacture. In accordance with one feature of the present invention,the pattern of the died-out blank for forming a cone is such that thetrailing edge of one blank coincides with the leading edge of asucceeding blank, thus eliminating waste between successive blanks.Also, the present pattern takes up the full width of the web or strip ofmaterial from which the blank is cut, thus providing a further saving ofthe material. Furthermore, in the prior art the pattern of the gauzematerial for covering the openings through which the material isstrained was such that the leading and trailing edges were spaced apartwhen cut from a strip of gauze, thus resulting in waste material. Inaccordance with the present invention, the leading and trailing edges ofthe gauze pattern coincide with each other and the pattern takes up thefull Width of the strip of gauze, thus eliminating entirely waste ofgauze material in the production of the conical paint strainers.

In the use of the prior conical paint strainers, it was found that theoverlapped adhesive seam was subject to attack by acrylic lacquer paintsand thinners so that after use if it was picked up to dispose of thesame, it would fall apart at the side seam. Such prior cones had arelatively narrow adhesively secured overlapped seam. In accordance withanother feature of the present invention, the structure of the conicalstrainer has been improved to provide a relatively larger overlapped andadhesively secured area at the side seam, such larger overlapped areaadding rigidity to the completed strainer. In addition, the larger areaof the seam serves as an obstruction to prevent the acrylic lacquer orthinners from bleeding through or destroying the seam during the timethe strainer is in use.

In accordance with another feature of the invention, the present conicalstrainer is provided with two opposed handles extended from theperiphery of the upper edge of the cone. The handle extensions arerelatively short and are formed integrally with the blank during thedie-cutting operation. Each handle is also provided with an opening. Inuse, the handles may be grasped to place or remove the disposablestrainer in position whereby to avoid transferring paint or the like tothe fingers. The provision of the openings in the handles affords aconvenient hole through which a rod may be passed for supporting andstoring a plurality of conical strainers in nested relation.

The present invention further contemplates a novel method of producingthe present conical paint strainers whereby a more rigid and efiicientpaint strainer having handles may be produced with substantial savingsin paper and gauze.

Referring now to the drawings, and particularly to FIGS. 1-3, thedisposable filtering device produced in accordance with the presentinvention is herein illustrated as comprising a conical member offibrous material, such as heavy paper. The conical member 10 is formedfrom a die-cut blank 12 provided with openings 14 which are covered witha filtering material, such as a coarse gauze 16 adhesively secured tothe marginal edges of the openings. The conical member '10 is providedwith a relatively wide overlapping adhesively secured side seam 18. Thedied-out blank 12 is further provided with projections 20 formedintegrally with the blank and which comprise opposed handles in theassembled filter. The handles 20 are also provided with openings 22 asshown.

As diagrammatically illustrated in FIGS. 4 and 5, the steps in themethod of making the present conical filtering device comprisedie-cutting successive blanks 12 from a strip or web 24 of fibrous blankforming material, such as a heavy paper or the like. In operation, theweb 24 is withdrawn from a supply roll thereof, not shown, and theleading end of the web is introduced between intermittently operatedfeed rolls 26 and 28 which are arranged to advance the web apredetermined distance each cycle of operation. In the illustratedembodiment of the invention, for example, the length of web advancedeach cycle is five and three-quarters inches.

At the first station of operation, a pair of registration holes arepunched along opposite marginal edges of the web which form the openings22 in the handles 20 as shown. The registration holes may be punched byvertically reciprocable punch and die units, not shown, during the idleperiod of the web. The web is then advanced to the second station ofoperation where a vertically reciprocable steel rule cutting die,delineated by the lines 34, 35, 36, 37 and 38, is operated to partiallycut the blank at station 2 during the idle time of the web and tosimultaneously complete cutting of the trailing end of the precedingblank which was advanced to and is now disposed at a third station ofoperation. It will be observed that the trailing end of the blank at thesecond station of operation is uncut except at the sides 36 adjacent theopenings 22 and also at the central portion 38. It will also be observedthat the lines 36 at station 2 delineate one side of the handleextensions 20. At the leading end of the blank at station 2, theremainder of the handles 20 are die-cut. Also, the lines 34 and 35 whichcomplete the cut between lines 36 and 38 are die-cut by the leading endof the die and which coincides substantially with the trailing end ofthe blank at station 3. The portions 37 of the steel rule cutting dieform the openings 14 in the blank.

As hereinbefore stated, the steel rule die members disposed at station 2effect partial cutting of the blank at this station, the cut beingcompleted on the trailing edge of the blank disposed at station 3. Thecut at the trailing end is completed after the strip has been moved adistance of five and three-quarters of an inch from station 2 to station3. As herein shown, the blanks at stations 2 and 3 are held together byrelatively small uncut portions along the steel rule cutting band, asindicated at 48, for the purpose of maintaining registration of theblanks with the cutting dies during successive cutting operations. Thesesmall uncut portions may be produced by making nicks in the steel rulecutting bands at the points 48 as indicated.

At station 3, the registration openings 22 are applied over pins 40carried by intermittently movable chains 42 which run over sprockets 44and 46, see FIGS, 5 and 6. The pins 40 carried by the chains are spacedapart longitudinally a predetermined distance, actually six inches inthe illustrated embodiment, such distance being a short distancegreater, that is one-quarter of an inch greater, than the distancebetween successive pairs of openings 22 as advanced by theintermittently operated feed rolls 26, 28. Thus, in operation, when theblank at station 3 engaged with the pins 40 is advanced to station 4, adistance of six inches, the blank at station 4 is separated from theblank at station 3 by tearing the same at the uncut portions 48.

From the description thus far, it will be seen that successive blankscut from the strip 24 by the die-cutting operations occupy the fullWidth of the web and that the handles 20 are formed in marginal portionsof the web which would otherwise be waste material. It will be observedthat the lines defining the outer ends of the handles are V-shaped andthat one of said lines, 21, represents the marginal edge of the web 24.As illustrated in FIG. 4, a minimum of waste material is produced inaccordance with the present method, the waste being indicated at opposedareas 50, 52, opposed areas 54, 56 and a central area 58 adjacent thetrailing end which delineates the center of the cone in the assembledfiltering device when the seam forming portions 60 and 62 areoverlapped. The died-out openings 14 also produce waste material.

During the time that the blank 12, separated from the web 24, is at reststation at 4, the waste material which is retained in place by therelatively small uncut portions 48 are removed in any usual or preferredmanner. In practice, vertically reciprocable upper and lower clampingunits are arranged to grasp the waste sections to forcibly remove thesame downwardly upon breaking or tearing the material at the uncutportions 48 of the blank whereupon the sections are released.

During the intermittent movement of the blank through various of thesucceeding stations of operation, the blank may be printed with the nameof the paint manufacturer or distributor, the printing roll beingindicated diagrammatically at 64 and which is provided with acooperating presser roll 66. Also, during such intermittent movementbetween subsequent stations, a coating of adhesive is applied to theside seam portion 60 and to the marginal edges of the openings 14 overwhich the gauze is subsequently applied. The adhesive applying roll isdiagrammatically indicated at 70 and is also provided with a cooperatingpresser roll 72. It will be observed that the adhesive coated area forthe side seam 60, as indicated at 74 in FIGS. 1 and 5, resembles ateardrop in shape, being relatively wide at the outer end thereof andtapering radially inwardly toward the cut out portion 76 which willsubsequently form the center or point of the assembled cone. The coatedarea 74 represents the area of overlap of the marginal edges whichaffords more rigidity in the assembled cone, and more protection againstthe etfects of paint or paint solvents which might destroy the adhesiveseal. The extra width of the overlap portions along each marginal edgerepresents what formerly was waste material in the prior art paintstrainers.

After the adhesive applying operation, a strip 78 of gauze withdrawnfrom a supply roll 80 thereof is cut to provide a substantially V-shapedsection 16 of gauze for application over the openings 14. In practice, agauze applying roller 82 provided with means for gripping andsubsequently releasing the leading end of the gauze Section 16 isintermittently rotated to advance the strip one section in lengthwhereupon the section is severed and the roll continues to rotate toelfect application of the gauze section over the openings 14 uponmovement of the blank and rotation of the roll to adhesively secure thegauze to the marginal edges of the openings. A co- Operating presserroll 83 may also be provided as shown. In practice, the strip 78 may beprovided with spaced punched openings 85 corresponding to the width ofthe severed section so that the cutters, not shown, may operate withtheir ends in the cutout space without interference of the cutters onewith the other.

It will be observed that the V-shaped gauze section 16 is formed fromthe full width of the supply roll 80 and that the marginal edges of theV-shaped section are substantially parallel to the marginal edges of theopenings 14. Thus, it will be noted that successive gauze sections 16cut from the strip 78 are wholly applied to the blank without producingany waste material. During intermittent movement of the gauze carryingblank through a following station of operation, upper and lower squeezerolls 84, 86 serve to press the gauze into firm engagement with theadhesive. It will be understood that the presser rolls will be shaped toavoid interference with the adhesive applied to the side seam 68. Fromthe description thus far it will be seen that successive blanks died outand separated from the strip are engaged by the pins of the chainconveyer 42 and are intermittently moved in spaced relation through thevarious operating stations until they arrive at the final station ofoperation as shown in FIG. 6.

At the final station of operation along the chain conveyor 42, the blankis advanced beyond the conveyer to be straddled between suitablesupports 88 and the blank is then removed from the pins 40. The blankthus supported free of the chains 42 and pins 40 is in position to beengaged by one of a plurality of cone forming mandrels 90 which areradially arranged about a center 91. In operation, the mandrels areintermittently rotated through several stations to engage the blank 12;to wrap the blank about the mandrel; to seal the side seam; and toremove the cones from successive mandrels to form a stack thereof.

As illustrated in FIGS. 7 and 8, each cone forming mandrel 90 iselongated at its upper end to provide flat triangular sides 92, 94 whichtaper down to a point 95, and curved end portions 96, 98 which alsotaper down to the point 95. The advantage of having an elongated andfiat sided mandrel is that it is more convenient to shape the blankabout the flat sides and to thereafter apply pressure to set the sideseam against a flat surface than it would be if the folding, pressingand discharging elements had to conform to the conical shaped side.Also, the relatively narrow fiat sided mandrels take up less spacebetween stations of the radially arranged units. In practice, it wasfound that immediately upon removal of the filtering device from theforming mandrel it assumes a conical shape.

As herein illustrated, upon engagement of the elongated shaping mandrel90 with the blank 12, as shown in FIG. 8, the blank is gripped along theforward marginal edge by grip fingers 100 carried by the mandrel. Themandrel is then moved through one station of operation, and during suchintermittent movement, suitable mechanism, not shown, is provided forwrapping the sides of the blank about the mandrel to present the sideseam portions 60, 62 in overlapping relation, as shown in FIG. 9, andfor applying pressure to the seam to set the same. The pressure applyingmeans, not shown, is maintained in engagement with the seam 18throughout the next station of operation. The last operating stationcomprises the discharge station. After the pressure applying means iswithdrawn and the grip fingers 100 are released, the cone is engaged bya longitudinally reciprocable suction member 102 arranged to strip thecone from the mandrel and to transfer the same onto a support 104 innested relation to previously transferred conical filtering devices 10.In practice, provision is also made for counting the number of devicestransferred to form a stack of a predetermined number thereof on thesupport 104 for convenience in packing the filtering devices.

In practice, the present paint strainer may be conveniently stored foruse by supporting the same in stacked relation on a horizontal rodextending from a wall or other support, the rod being extended throughone of the openings 22 of each strainer. Such paint strainer supportingrod may be placed under a bench or other protective place to keep thestrainers free of dust or other foreign matter and also as a convenientstorage space from which individual strainers may be easily removed.

From the above description, it will be seen that the present disposablefiltering device and method of making same provides a novel andefiicient structure of filtering device particularly adapted forstraining paint whose structure provides increased rigidity and whereinthe steps in the method of making the filtering device permit the sameto be economically and rapidly produced.

While the preferred embodiment of the invention has been hereinillustrated and described, it will be understood that the invention maybe embodied in other forms within the scope of the following claims.

Having thus described the invention, what is claimed is:

1. The method of making a disposable cone shaped filtering device havinggauze covered openings comprising the steps of intermittently advancinga web of sheet material of predetermined width a distance of one blanklength each advancing movement, die-cutting successive blanks from theweb while the web is at rest, each blank utilizing the full width of theweb, said die-cutting operation leaving small uncut frangible portionsbetween the leading and trailing ends of the blanks, the trailing end ofone blank coinciding with the leading end of a succeeding blank,separating the leading blank from the web by breaking the frangibleportions, applying and adhesively securing a section of gauze over thedied-out openings, and wrapping the blank about a mandrel with themarginal edges in overlapping relation and adhesively securing the same.

2. The method as defined in claim 1 which includes the steps of applyingadhesive to selected portions of successive blanks.

3. The method as defined in claim 1 which includes the steps of cuttingsuccessive sections of gauze from a strip thereof and applying the sameover the openings, each section being defined by the full width of thestrip, and the leading and trailing ends coinciding with each otherwhereby to eliminate waste of gauze material.

4. The method as defined in claim 1 wherein the died-out openings andmarginal waste portions are also retained by small uncut frangibleportions, and which includes the step of removing said waste portions byrupturing said frangible portions.

5. The method as defined in claim 1 wherein the mandrel for producingthe cone shaped member is oval in plan and triangular in side elevationproviding flat side walls against which the adhesive seam may bepressed, said cone shaped members assuming a conical shape upon removalfrom the mandrel.

6. The method as defined in claim 1 which includes the steps of removingthe filtering devices from successive mandrels, and stacking the same innesting relation.

7. The method of making a cone shaped filtering device having at leastone opening therein comprising the steps of cutting successive blanks ofsheet material from a web thereof by making successive arcuate cuts inthe web whereby to form the convex trailing edge of one blank and theconcave leading edge of the next successive blank, cutting openings inthe blank, forming in the marginal edges of the blanks handles, eachblank being 7 the full width of the Web, and cutting a blank offiltering material having openings therein and applying said blank offiltering material over said openings in the sheet material.

References Cited UNITED STATES PATENTS 752,019 2/1904 Adwen 210-4971,983,323 12/1934 Stokes ....156-514 8 2,273,422 2/1942 Schroeder210-497 3,049,121 8/1962 Brumfield et a1 55-521 3,156,597 11/1964Nadaline, Jr. 156514 5 DOUGLAS J. DRUMMOND, Primary Examiner US. Cl.X.R.

